Our Liriiii^ Rtwcmxcs — Blnls 



79 



significantly affect annual productivity for the 

 species. A similar threat to piping plovers occurs 

 on Lake Diefenbaker in Saskatchewan, the 

 largest piping plover breeding site in the world, 

 where each year water levels are raised soon 

 after parents ha\e laid their clutches, resulting in 

 a loss of all nests. 



Avian and mammalian predation is a problem 

 throughout the species" breeding range, although 

 population numbers appear to be stabilizing on 

 the Atlantic coast and the Great Lakes as a result 

 of using predator exclosures over nests (Rimmer 

 and Deblinger 1990; Mayer and Ryan 1991; 

 Melvin et al. 1992). Human disturbance contin- 

 ues to be a problem on the Atlantic coast (Strauss 

 1990), and in the Great Lakes, piping plovers 

 may also be suffering from a lack of viable habi- 

 tat (Nordstrom 1990). Comparison of food avail- 

 ability at northem Great Plains sites with Great 

 Lakes sites indicated lower diversity and abun- 

 dance of invertebrates on the Great Lakes. 

 Finally, recent evidence suggests that Great 

 Lakes birds may be suffering from high levels of 

 toxins (i.e.. PCB's). which may be a prime factor 

 in low productivity and population growth 

 (USFWS, East Lansing. Michigan, personal 

 communication). 



The discovery of the high proportion of win- 

 tering piping plovers on algal and sand flats has 

 significant implications for future habitat pro- 

 tection. Current development of these areas on 



Piping plover [Charadrius melodiis). 



Laguna Madre in Texas and Mexico, increased 

 dredging operations, and the continuous threat 

 of oil spills in the Gulf of Mexico will result in 

 serious loss of piping plover wintering habitat. 



In summary, piping plovers suffer from many 

 factors that may cause their extinction in the 

 next 50 years. Most devastated are the Great 

 Lakes and northem Great Plains birds whose 

 viability is severely threatened. Unfortunately, 

 recovery is hindered by a lack of knowledge 

 about the winter distribution, status of winter 

 sites, adequate water-management policy in 

 western breeding sites, and direct human distur- 

 bance on the Atlantic coast. 



Table i. Changes in numbers of 

 pipnig plovers at specific breeding 



'Sources are listed in Haig and Oring (1985) and Haig and Plissner 

 (1993) 



References 



Haig. S,M. 1992, The piping plover. Pages I-IS in A, Poole, 

 P. Stettenheini. and F. Gill, ed. Birds of North America. 

 American Ornithologists' Union. Washington. DC. 



Haig. S.M,. and L,W. Oring. \9?,5. Distnbution and status 

 of the piping plover throughout the annual cycle. Journal 

 of Field Ornithology 56:334-345. 



Haig. S.M.. and J.H. Plissner 1993. Distribution and abun- 

 dance of piping plovers: result.s and implications of the 

 1991 International Census. Condor 95:145-1.56. 



Mayer. P.M.. and M.R. Ryan, 1991. Electric fences reduce 

 maninialian predation on piping plover nests and chicks. 

 Wildlife Society Bull. 19:59-62. 



Melvin. S.M.. L.H. Maclvor. and C.R. GntTin. 1992. 

 Predator exclosures: a technique to reduce predation at 

 piping plover nests. Wildlife Society Bull. 20:143-148. 



Nordstrom. L.H. 1990. Assessment of habitat suitability for 

 reestablishment of piping plovers on the Great Lakes 

 National Seashores. M.S. thesis. University of Missouri. 

 Columbia. 36 pp. 



Rimmer. D.W., and R.D. Deblinger 1990. Use of predator 

 exclosures to protect piping plover nests. Journal of 

 Field Ornithology 61:217-223. 



Ryan, MR.. B.G. Root, and RM. Mayer 1993. Status of the 

 piping plover in the Great Plains of North America: a 

 demographic simulation model. Conservation Biology 

 7:581 -.591. 



Schwalbach. M.J. 1988. Conservation of least terns and pip- 

 ing plovers along the Missouri River and its major tribu- 

 taries in South Dakota. M.S. thesis. South Dakota State 

 University. Brookings. 43 pp. 



Sidle. J.G.. D.E. Carlson. E.M. Kirsch, and J.J. Dinan. 1992. 

 Flooding: mortality and habitat renewal for least terns 

 and piping plovers. Colonial Waterbirds 15:132-136. 



Strauss. E. 1990. Reproductive success, life history patterns, 

 and behavioral variation in a population of piping plovers 

 subjected to human disturbance. Ph.D. dissertation. Tufts 

 University, Boston. MA. 123 pp. 



For further information: 



Susan M. Haig 



National Biological Service 



Forest and Range Ecosystem 



Science Center 



Oregon State University 



3200 SW Jefferson Way 



Corvallis, OR 97331 



